No.3（2000）24.Effects of Helium Ions of an Early Embryo on Postembryonic Leaf Development in Brassica napus L

Noboru SAKURAI, Harufumi MINAMI, Naoya SHIKAZONO, Atsushi TANAKA, Hiroshi WATANABE

We examined postembryonic effects after helium ion and gamma ray irradiation of an isolated whole flower (a flower with pedicel) of Brassica napus through a flower organ culture, and estimated the effects of irradiation on embryogenesis in sexual reproductive stages. The whole flowers were irradiated with 30 Gy of helium ions and gamma rays in the early globular embryo and/or torpedo embryo stages. The helium ion and gamma ray irradiation of early globular embryos caused some drastic malformations in the first true leaves. Those malformations were classified into four types: cup-shaped, funnel-shaped, shrunk and the other varied leaves. The types were observed in 40 % of plants that developed first true leafs. Both cup-shaped and funnel-shaped types were observed in over 15 %. On the other hand, the irradiation of gamma rays of torpedo embryos caused sectors lacking chlorophyll in first true leaves.

Keywords
Brassica napus L., cup-shaped leaf, embryo, flower organ culture, funnel-shaped leaf, gamma rays, helium ions, postembryonic development

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